When producing frozen extruded ice cream products, it is a common practice to place extruded pre-products to be frozen onto product plates arranged on a conveyor and then to convey the pre-products through a freezing apparatus, often in the form of a freezing tunnel, for cooling the pre-products so that they leave the freezing apparatus again as frozen products.
The degree, to which the products are frozen when passing through the freezing apparatus, is a very important parameter of the production process. Whereas the pre-products are relatively sticky and, to some extent, adhere to the product plates, the frozen products are less sticky the harder they are frozen.
This means that, if the products are not sufficiently frozen, they stick too much to the product plates and may be damaged when trying to remove them therefrom. On the other hand, if the products are subject to excessive freezing, they may loosen completely from the product plates and fall off the product plates on their way through the freezing apparatus. This may, for instance, happen, where there is a curve or a turn on the conveyor, or due to flows of cooling air inside the freezing apparatus.
In freezing systems known in the art, it requires skilled and experienced operators to ensure that the freezing process is performed optimally, so that neither insufficient nor excessive freezing of the products takes place in the freezing apparatus.